Files
chipsec-chipsec/chipsec/utilcmd/decode_cmd.py
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2017-06-08 18:42:55 -07:00

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4.6 KiB
Python

#!/usr/bin/python
#CHIPSEC: Platform Security Assessment Framework
#Copyright (c) 2010-2015, Intel Corporation
#
#This program is free software; you can redistribute it and/or
#modify it under the terms of the GNU General Public License
#as published by the Free Software Foundation; Version 2.
#
#This program is distributed in the hope that it will be useful,
#but WITHOUT ANY WARRANTY; without even the implied warranty of
#MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
#GNU General Public License for more details.
#
#You should have received a copy of the GNU General Public License
#along with this program; if not, write to the Free Software
#Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
#
#Contact information:
#chipsec@intel.com
#
"""
CHIPSEC can parse an image file containing data from the SPI flash (such as the result of chipsec_util spi dump). This can be critical in forensic analysis.
Examples:
chipsec_util decode spi.bin vss
This will create multiple log files, binaries, and directories that correspond to the sections, firmware volumes, files, variables, etc. stored in the SPI flash.
.. note: It may be necessary to try various options for fw_type in order to correctly parse NVRAM variables. Currently, CHIPSEC does not autodetect the correct format. If the nvram directory does not appear and the list of nvram variables is empty, try again with another type.
"""
import os
import time
from chipsec.file import read_file, write_file
from chipsec.command import BaseCommand
import chipsec.hal.spi as spi
import chipsec.hal.spi_descriptor as spi_descriptor
import chipsec.hal.spi_uefi as spi_uefi
import chipsec.hal.uefi as uefi
class DecodeCommand(BaseCommand):
"""
>>> chipsec_util decode <rom> [fw_type]
For a list of fw types run:
>>> chipsec_util decode types
Examples:
>>> chipsec_util decode spi.bin vss
"""
def requires_driver(self):
return False
def run(self):
if len(self.argv) < 3:
print DecodeCommand.__doc__
return
_uefi = uefi.UEFI( self.cs )
if self.argv[2] == "types":
print "\n<fw_type> should be in [ %s ]\n" % ( " | ".join( ["%s" % t for t in uefi.uefi_platform.fw_types] ) )
return
rom_file = self.argv[2]
fwtype = self.argv[3] if len(self.argv) == 4 else None
self.logger.log( "[CHIPSEC] Decoding SPI ROM image from a file '%s'" % rom_file )
t = time.time()
f = read_file( rom_file )
(fd_off, fd) = spi_descriptor.get_spi_flash_descriptor( f )
if (-1 == fd_off) or (fd is None):
self.logger.error( "Could not find SPI Flash descriptor in the binary '%s'" % rom_file )
return False
self.logger.log( "[CHIPSEC] Found SPI Flash descriptor at offset 0x%x in the binary '%s'" % (fd_off, rom_file) )
rom = f[fd_off:]
# Decoding Flash Descriptor
#self.logger.LOG_COMPLETE_FILE_NAME = os.path.join( pth, 'flash_descriptor.log' )
#parse_spi_flash_descriptor( self.cs, fd )
# Decoding SPI Flash Regions
# flregs[r] = (r,SPI_REGION_NAMES[r],flreg,base,limit,notused)
flregs = spi_descriptor.get_spi_regions( fd )
if flregs is None:
self.logger.error( "SPI Flash descriptor region is not valid" )
return False
_orig_logname = self.logger.LOG_FILE_NAME
pth = os.path.join( self.cs.helper.getcwd(), rom_file + ".dir" )
if not os.path.exists( pth ):
os.makedirs( pth )
for r in flregs:
idx = r[0]
name = r[1]
base = r[3]
limit = r[4]
notused = r[5]
if not notused:
region_data = rom[base:limit+1]
fname = os.path.join( pth, '%d_%04X-%04X_%s.bin' % (idx, base, limit, name) )
write_file( fname, region_data )
if spi.FLASH_DESCRIPTOR == idx:
# Decoding Flash Descriptor
self.logger.set_log_file( os.path.join( pth, fname + '.log' ) )
spi_descriptor.parse_spi_flash_descriptor( self.cs, region_data )
elif spi.BIOS == idx:
# Decoding EFI Firmware Volumes
self.logger.set_log_file( os.path.join( pth, fname + '.log' ) )
spi_uefi.decode_uefi_region(_uefi, pth, fname, fwtype)
self.logger.set_log_file( _orig_logname )
self.logger.log( "[CHIPSEC] (decode) time elapsed %.3f" % (time.time()-t) )
commands = { "decode": DecodeCommand }